This is the story of Project Orion, a scheme during the 1950s and 60s to build a huge interplanetary vehicle powered by a series of controlled atomic explosions. At its heart is the figure of British mathematician and physicist Freeman Dyson, a man who happily admits there is a good deal of truth in the image of the “mad scientist”.

But Orion was not as crazy as it sounds, and, as Arthur C Clarke says, the question may well have been whether we should, rather than whether we could, have carried it out. Most of all, the film offers material for reflection about science itself, the people who do it and their motives. An inspiration and a warning for all apprentice boffins out there.